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Old 05-07-2014, 09:17 PM   #701 (permalink)
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Quote:
Originally Posted by GONRACIN View Post
Has anyone tried this? I find it's very...interesting. And possibly useful.

Bolt-together AR-15 lower receiver: no 3D printer necessary
Seabass posted that back at #144, I don't think those plans ever showed up. {till now of course}

I posted the KT in #145.
Remember KT Ordanance's screw together lower reciever? - Calguns.net




A club buddy brought one of the KTs to a meeting for showNtell. It looked a lot better (more curves) than the diy version.

The thread also went down the steel plate rabbit hole and ended up HeRe.



Pretty healthy discussion over at weapons guild. The steel had several issues including warpage, weight and fit at the rear takedown.

Last edited by rocket flier; 05-08-2014 at 12:20 AM.
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Old 05-09-2014, 04:04 PM   #702 (permalink)
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I couldn't find if it was mentioned but I'm using an end mill in a drill press to finish up all the drilled holes. What RPM should I be using ? As slow as possible (600rpms)or as fast as possible (2800rpms)Or in the middle??
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Old 05-09-2014, 04:55 PM   #703 (permalink)
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Old 05-09-2014, 05:26 PM   #704 (permalink)
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I couldn't find if it was mentioned but I'm using an end mill in a drill press to finish up all the drilled holes. What RPM should I be using ? As slow as possible (600rpms)or as fast as possible (2800rpms)Or in the middle??
.
10 Tips for CNC Router Aluminum Cutting Success - CNCCookbook CNC Blog CNCCookbook CNC Blog

Finish pass speed and RPM?

Quote:
Paul T.

Figuring your SFM (Surface Feet/Minute, which will determine your RPM)

SFM with HSS endmills
Stainless Steel 40
Mild Steel 100
Brass 300
Aluminum 400

With carbide endmills, multiply those settings by 3 as a starting point, so:
SFM with Carbide Endmills
Stainless Steel 120
Mild Steel 300
Brass 900
Aluminum 1200

Then:

RPM = 4 x SFM/Diameter

Now to find your feed, first calculate your chip load. A reasonable starting point for the chip load is to divide your endmill diameter by 200.

Chip Load = Diameter/200

Then to calculate your Feed Rate:

Feed Rate= RPM x Num of Teeth x Chip Load

So for example with a 1/4" HSS endmill in steel, your RPM should be:

RPM = 4 x 100/.25 = 1600

Your feedrate should be:

Feed Rate = 1600 x 2 x .25/200 = 4 ipm

This a starting point, I usually crank down a little from these recommended settings to see how the machine responds.

As far as your maximum depth of cut, on smaller machines this is often determined by the available spindle HP you have. However if the machine is up to it, I use the following guidelines for max radial and axial cut (borrowed from Stan Dornfeld):

Slotting: Cut Depths
6061 Aluminum, Brass - 1/2 endmill diameter
7075 Aluminum - 40% endmill diameter
Mild Steel - 30-35% endmill diameter
Stainless Steel - 25% endmill diameter

Rough Profiling Tool Overlap: 70% endmill diameter or less
Finish Profiling Tool Overlap: 3% endmill diameter

Plunging Rates:
Take the normal slotting feedrate and divide by the number of flutes.
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Old 12-08-2014, 09:24 AM   #705 (permalink)
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Anyone heard of United Armory? They were selling 80%s and jigs and when I walked by their booth, they had my little drawing hanging there. Asked if he was on pirate he mumbled something about internet.


Someone called Fisher Solutions posting it too:
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Old 12-15-2014, 12:28 PM   #706 (permalink)
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Thread bump here:

Seasons Greetings all. So, I finally got my setup and have started makin chips. Oh yeah!

Anyhow, I got the whole front pocket milled out last night on the first lower I tried out. I went down to about 1.22 inches (short of the 1.249 max depth) and was going back around cleaning up the sides... Well, this is when life went to suck mode for me. Somehow, my end mill grabbed the bottom and slowly pulled the jig up from the vice...

By the time I realized it, the end mill chewed the pocket depth down to 1.35 in a second... I shouted some nice choice words after that and chucked the thing on my desk as a new paperweight...

So, the jig I am using is the Juggernaut Tactical one (AR-15 80% Lower Adjustable Universal Jig Kit) and a lower receiver that I bought 2 yrs ago and can't remember the brand...

The thing I noticed is that there are two main plates that are on both sides of the lower and there is nothing really touching the trigger area and etc on the lower. So. basically.. there is a bunch of blank space in there that I am reaming down on with the vice... I think the chatter is loosing it temporarily and then making it pop up in the vice while milling... This is a problem methinks

I also was using the ATF fluid to cut which works great, but I think the fluid slicked up the jig and sped up my blunder here... The Jig slipped up on me once very early in the process as well and I reamed it down pretty good at that point and checked it like one other time while milling...

My question is how will I account for this? I am going back out for attempt #2 in about 2 hours on the next lower in the same setup. I am very nervous though that this jig will pull back up on me again during milling... Even if I check it and re-tighten it on every pass, I am nervous the thing will pull up on me mid pass...

Does anybody have any idea here for me for what to do? I am going to take a good look at some of the items in my clamp kit to fixture the jig to my vice basically so this won't happen...

Also, I have the billet80.com jig and 2 billet80 lowers that I will be doing next after this other one and I hope there is more stability in the jig to clamp on than the setup I am rolling with on the JTactical jig and this random lower I am milling... I hope I won't have another paperweight on my hands because of this jig issue... Super PO'ed though after this blunder on the first go...

Thanks in advance for any help!

**Edit: I was making less than .100 passes as well (on the bottom of the pocket that is on each pass). It took me about 3 1/2 hours to mill out the pocket this way. So, I was taking my time. This is a jig issue slipping in the vice. The end mill is gripping the material and slipping the jig up on me in the vice... I reamed the thing down, but I think there is flex in those jig plates as it is just empty space. Maybe wood spacers or something in there to make more of a fixture?

Last edited by Bison9; 12-15-2014 at 12:43 PM.
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Old 12-15-2014, 01:52 PM   #707 (permalink)
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Here's what I did.... Did this before I even attempted to mill my first lower, and haven't had any problems. Sure made the jig seem more solid to me.





As you can see those two spacers are right outside the width of my milling machine vise.

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Old 12-15-2014, 01:53 PM   #708 (permalink)
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By the time I realized it, the end mill chewed the pocket depth down to 1.35 in a second... I shouted some nice choice words after that and chucked the thing on my desk as a new paperweight...
Unless I'm missing something, that's fixable. The whole trigger pocket ended up at 1.35? If yes, shim it. If no, may not even need to do anything.

Quote:
Originally Posted by Bison9 View Post
So. basically.. there is a bunch of blank space in there that I am reaming down on with the vice... I think the chatter is loosing it temporarily and then making it pop up in the vice while milling... This is a problem methinks

Does anybody have any idea here for me for what to do? I am going to take a good look at some of the items in my clamp kit to fixture the jig to my vice basically so this won't happen...
Make a spacer that will fit in the trigger area so you're actually clamping the 2 sides together. Shimming between the jig and part would do the same thing.
Quote:
Originally Posted by Bison9 View Post
I reamed the thing down, but I think there is flex in those jig plates as it is just empty space. Maybe wood spacers or something in there to make more of a fixture?
You're getting vertical movement which is bad, but you could also be getting horizontal movement. You could make shift a hold down to help out too.
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Old 12-16-2014, 04:35 AM   #709 (permalink)
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I have made slip in spacers for all my jigs as none support that area
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Old 12-17-2014, 07:17 AM   #710 (permalink)
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Oh, hello there..!

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Old 12-17-2014, 07:30 AM   #711 (permalink)
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And that is how a complete noob/moron scratches out a lower receiver

No, in all seriousness though, I did not even have a shop/setup when I started this a year ago. Made my own shop, worked all the bugs out of all the equipment I bought up front, and finally got to this lower! It took me all of 2014 to do it but it finally got done...

So... I ended up clamping the crap out of this thing. Pics below are the right side, left side, and front facing shot of what I ended up doing to clamp the thing into place. I basically went to odds and ends in the clamp kit I bought to accomplish this. The Kantilever clamps really helped too This basically fixtured it for me.

I reamed the vice down way, way harder too this time on the second go. I learned so much from the first blunder just about machining in general. I milled out a test bar before the first one even and there were way less variables in the test bar than the jig with the lower. It takes the first one in the jig to figure stuff out I think as a complete machining rookie..

Once I worked these bugs out and figured this out, this Juggernaut tactical jig is very nice. The plates are hardened and are very nice. My lowers from billet80 fit the JTactical jig as well and I think I am going to use it for those too. I bought the jig from billet80 as well but I really like this JTactical one.

Doc is absolutely right though. You make a pass, you measure. You constantly measure. I noticed that checking my DRO zero frequently is a must. And checking the whole setup in the vice frequently etc is very key as well...

Anyhow, the lowers I have from billet80 are next (the 4th pic below)!







The billets are next!


Last edited by Bison9; 12-17-2014 at 07:40 AM.
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Old 12-17-2014, 07:46 AM   #712 (permalink)
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Once I get these 2 billet lowers done and get all 3 sand blasted and duracoated (that's what I am deciding unless somebody can tell me who I can send these to in order to get them Type III Anodized), I will write a complete writeup of my setup with links and whatnot for what I used.

I bought 14 end mills (I kid you not) up front so I could try a bunch of them and you only need the 3/8 carbide one from JTactical and the 1/4" carbide one (with the H drill bit) also from JTactical for the trigger slot. And that is literally it for end mills. If you are a noob reading this, just get the tooling package from JTactical and that is literally all you need. It saves hours researchng end mills and looking at literally 1,000's of choices and quite frankly, utterly terrible information on the the web concerning what you actually need for this project.

Oh Yeah, the carbide end mills are way, way, way, quadruple way better than anything else I put to this lower. It wasn't even close. I had 12 other end mills from Enco that were $14 a piece and they were not even close to as nice as the 2 carbide ones from JTactical.

It will take me probably a month, but when everything is finished, I will put a complete writeup here of what I used/did.

Last edited by Bison9; 12-17-2014 at 07:53 AM.
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Old 12-17-2014, 07:48 AM   #713 (permalink)
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Oh, and one last thing for now... The 1/2" wheel lugs and MFG gussets for the vice worked wonders. If you want that setup not to move... You use those....

Last edited by Bison9; 12-17-2014 at 07:52 AM.
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Old 12-17-2014, 10:38 AM   #714 (permalink)
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Quote:
Originally Posted by Bison9 View Post
Oh, and one last thing for now... The 1/2" wheel lugs and MFG gussets for the vice worked wonders. If you want that setup not to move... You use those....
I believe that idea came from somewhere.....not sure
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Old 12-17-2014, 01:40 PM   #715 (permalink)
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Yep, it was that tip and many others on this thread that allowed me to have success! Many Thanks!
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Old 12-17-2014, 01:45 PM   #716 (permalink)
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The other thing I can say for the noob reading this is that the process at the link below is way faster in my mind on the drill press actually. Doing this on the mill without pre drilling took a very long time. It is very tedious. I also got good at turning both handles at the corners in my final run ups. That took time to learn.

It seems to me that you better have a sturdy drill press if you do this method....

Link: https://www.youtube.com/watch?v=ZKz2sLJUvGU
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Old 12-17-2014, 01:47 PM   #717 (permalink)
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I wish the price of 80s were in line with the current prices of complete. I love making my own guns and have done so plenty of times (and plan to in the future), but for throwing together AR it doesn't make sense $$ and time wise right now.

Is it a pipe dream to hope for ~$50 or less 80% receivers some day?
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Old 12-17-2014, 02:35 PM   #718 (permalink)
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Is it a pipe dream to hope for ~$50 or less 80% receivers some day?
Buy 5 and they are $49 each.
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Old 12-17-2014, 02:39 PM   #719 (permalink)
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Anderson's are at $45 each.
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Most 9 ' s are capable of firing 380 and if push really came to shove, you can fire .357 and 38 special through one.
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Old 12-17-2014, 02:39 PM   #720 (permalink)
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I wish the price of 80s were in line with the current prices of complete. I love making my own guns and have done so plenty of times (and plan to in the future), but for throwing together AR it doesn't make sense $$ and time wise right now.

Is it a pipe dream to hope for ~$50 or less 80% receivers some day?
$50 + shipping OK?
CODE=35OFF80
AR15 80% Billet Non-Anodized
ANODIZED $60 use the same code

$70 for their jig (I posted a $50 one in the blackfriday thread HERE)
AR15 JIG for 80% AR15 Paperweight

Copes is out of stock on the $45 anderson as well:
http://www.copesdistributing.com/and...te-p-8184.html

Last edited by rocket flier; 12-17-2014 at 02:51 PM.
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Old 12-19-2014, 07:30 PM   #721 (permalink)
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Originally Posted by LiLBucket View Post
I wish the price of 80s were in line with the current prices of complete. I love making my own guns and have done so plenty of times (and plan to in the future), but for throwing together AR it doesn't make sense $$ and time wise right now.

Is it a pipe dream to hope for ~$50 or less 80% receivers some day?

$46.95 each or $299.95 for five pack and jig combo.


80% Lower Receiver - AR-15 Parts
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Old 01-13-2015, 01:48 PM   #722 (permalink)
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Hey Doc, I see that media blasting cabinet in your vids. Is that what you used to media blast your lower in the video? If so, I am wondering what compressor you are using to power that with? What is the size of it basically?

I have a 15 gallon Bostich air compressor that runs a nitro cat air gun quite nicely... But, I only think it is pumping out like 5 CFM max at like 90 PSI...

However, this cabinet I am looking at requires 10 CFM at 100 PSI: Abrasive Sand Media Bead Blast Blaster Blasting Cabinet | eBay

Other cabinets require like 15 CFM.. Ugh

So... Unless I am missing something, my Bostich will be unsufficient to hook up to a media blasting cabinet like this one above??

As a side note, I am going to be using the Anodizing kit form Caswell's to Anodize. I have been studying up on this process since I finished milling those lowers a month ago and I almost know what I need for it all...

Thanks in advance!
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Old 01-13-2015, 01:56 PM   #723 (permalink)
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But, I only think it is pumping out like 5 CFM max at like 90 PSI...

However, this cabinet I am looking at requires 10 CFM at 100 PSI:
Add a (or multiple) reserve tanks tied together. The more volume, the better.
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Old 01-13-2015, 06:24 PM   #724 (permalink)
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I am running a 220v speedaire I robbed from Craigslist for like $150 I still feel I need bigger or add another 60-80gal tank when blasting
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Old 01-13-2015, 08:31 PM   #725 (permalink)
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Thanks for the replies!
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